Coating process and material



Patented Aug. 15, 1933 1,922,936 COATING raoorss AND MATERIAL Henry V. Dunham, Bainbridge, N. Y., assignor,

by mesne assignments, to The Casein Manufacturing Company of America, Inc., New

York, N. Y., a Corporation of Delaware No Drawing. Application March 21, 1929 Serial No. 348,997

- 7 Claims.

This invention has for its object the preparation and application of a first coating or undercoating or preparatory surface for wooden articles generally, and particularly furniture and wood panels, the invention also being applicable in the finishing of cloth, the making of artificial leather, special coatings for paper and the like, this undercoating being applied for the purpose of forming a satisfactory surface for subsequently coating- 10 with pyroxylin varnishes, such varnishes being also commonly known in. the trade as lacquer varnishes. The invention embraces both the process and product, as well as the coating composition. i

I have found that this process is partlcularly advantageous for the filling and coating of wood and will therefore, describe the character of this invention in detail more especially from the standpoint of the finishing of wood, although the invention is not limited to this one art.

When it is desired to finish with ordinary varnishes or paints, wooden objects, for example furniture, the furniture is (according to the prior practice) first sanded to secure a smooth surface same. When the furniture has been made ready for the finalfinishing it has heretofore been the practice to first fill or partially fill the pores of the wood (and especially the surface portions) with what is known in the art as a wood filler. This filler may be a weak water solution of animal glue, or gelatin or a solution of shellac, the shellac being dissolved in water with the aid of borax. Alcoholic solutions of shellac also often have been used,'and in many cases a drying oil containing silex, either made into a heavy paste and rubbed on to the surface of the wood or diluted with turpentine or other thinners and painted on the wood.

In more recent years attempts have been made to use aqueous alkaline solutions of casein for this purpose. Whatever the first coating or fill ing coat may be it is in some cases rubbed into the pores of the wood and in other cases painted or brushed on to the wood. If a thin mixture is used, the wooden articles may be dipped into a solution of the filler and the excess quantity of liquid allowed to run back on a draining board into the receiving tank.

In recent years the method of spraying fillers onto furniture has been largely developed. Whatever the means of application of the filler may be, the coated object after the filling operation, is allowed to stand a certain time to be come dry and seasoned before a subsequent sandprior to the actual varnishing and rubbing ofing and rubbing of the surface prior to the application of the finishing coats of pyroxylin varnish or lacquer and these finishing coats may be one or two or more, each coating being allowed to dry and in some cases rubbed and sanded prior to 0 the applying of the next coating. In recent years the advance in the application of pyroxylin varnish for the finishing of wood and the like has been very great. There are many advantages in its use over the older methods of 5 oil and resin gum varnishes. All of these features are well known to the art.

One of the great difiiculties encountered in the use of pyroxylin or lacquer varnishes, has been due to the difiiculty in securing a suitable filler coating for such varnishes, the difficulty,in this respect being due in my judgment to the fact thatthe lacquer or pyroxylin varnish applied to wood which has been filled with any of the fillers described above, will not properly unite with the filling coat since these filling coats contain no substances which are soluble in the lacquer varnish or in other words, the lacquer varnish does not blend with the filler, with the result that when the lacquer varnish is applied to wood which has been filled with these fillers it does not adhere or unite sufficiently with the filler coating, and as a result it will when dry, show considerable tendency to peel away or separate from the filler undercoat. This difficulty may not arise immediately after the furniture has been finished but there seems to be a gradual development of a separation of the lacquer film from the undercoat filler film. I believe that this separation is due to thefact that such undercoatings as glue, gelatin, casein, shellac and the like are not soluble in the solvents commonly used in dissolving pyroxylin and that therefore, when applying top coatings to wood and the like that has been filled with casein, glue, gelatin, shellac and the like, the pyroxylin coating has no opportunity of partially filling the pores of the wood or uniting with the undercoating "or filler coating to thus cause a strong bond, nor will it combine to any sufiicient extent with the first filler coating to form a united or partially united bond of the two coatings. By my novel process I am able to cause the subsequent pyroxylin varnish or lacquer coating to sufficiently unite with the filler coating in such a manner that the lacquer coating remains permanently fastened to the filler coating when water solutions of glue, gelatin or water alkaline solutions of casein or seed meals or vegetable protein substances are employed in the filler.

' solved casein.

In carrying out my invention I may use aqueous solutions of glue or gelatin, or alkaline aqueous solutions of protein substances such as casein, seed meal or protein from seed meals or substantially neutral solutions of casein, seed meals or protein of seed meals. However, my preferred method is the use of alkalized aqueous casein solutions or neutral aqueous casein solutions and the addition to such solutions of a suitable quan tity of the pyroxylin varnish or the lacquer of the general character of that which is to be used on the subsequent top coatings of the object to be finished.

In order that one skilled in the art may more clearly understand my process and product, I give herewith examples and my preferred method of preparing the material and applying same, although I am well aware that many other combinations and proportions may be made with satisfactory results. I, therefore, do not wish to limit this invention to the examples herein set forth.

Example 1.-21 parts of ground casein, 4 parts of borax, 100 parts of water, 5 parts pyroxylin varnish, 150 parts Water. The casein used may 'be an ordinary commercial grade, preferably ground to about 50 mesh. To this casein I add 4 parts of borax and 100 parts of water. A thorough mixing of these ingredients is necessary and if desired, a subsequent heating to about 160 F., may be employed or with constant stirring the casein will in time become perfectly dissolved in the cold. In any case after the casein has become completely dissolved and is substantially cold, 5 parts by weight of pyroxylin varnish are added and thoroughly mixed into or distributed through or emulsified in the casein solution. This mixture has a tendency to become somewhat thicker than the casein solution was prior to the adding of the pyroxylin varnish, and a change in color is apparent, the mixture becomes much whiter and more milky in appearance. After thoroughly mixing the pyroxylin varnish into the casein solution, the mixture may be diluted to the desired consistency by adding cold water, for example 150 parts of cold water to the above amounts. This is thoroughly stirred into the mixture when, if desired, the mixture may be strained through a fine wire sieve or the like to remove particles of dirt or particles of undis- The mixture is then ready to apply to the object that is to receive the filler coating, by any convenient method, say by brushing, dipping or spraying.

If the solution as described in Example 1 appears to be too heavy or produces too thick a coating on the object to be coated; the mixture may be further diluted as desired, with water or the like.

It is possible to also add any mineral fillers such as silex, finely ground'silica, talcum and the like, to assist in closing the pores of the wood.

When the object has received a filler coating of the material described in Example 1 it is allowed to thoroughly dry and harden, preferably for about ten or twelve hours or until practically all of the moisture in the coating has disappeared. The coated object may then be sanded or rubbed by the methods usually employed in the art of finishing if desired, and subsequently the pyroxylin varnish or lacquer coating or. coatings applied in the usual manner as by brushing, dipping or spraying.

Example 2.-The fillerv composition is made from 1 part lime, 2 parts sodium fluoride, 2 parts trisodium phosphate, 20 parts casein, 100 parts water, 5 parts pyroxylin varnish, 150 parts water.

The method of procedure and application is the I same as in Example 1 excepting it is preferable to use no heat in dissolving the casein and alkalies.

Example 3.The filler composition is made from 25 parts animal glue, 50 parts water, 5 parts pyroxylin varnish, 150 parts water. The 25 parts of animal glue are added to the 50 parts of cold water and allowed to-soak for several hours. It is then preferably heated to about 140 F., until the glue has become completely dis solved in the water. This solution is then cooled to about 100 F., and 5 parts of pyroxylin varnish added, thoroughly mixed into the glue and then 150 parts of warm water at about 100 F., are added. This mixture may then be diluted more if desired, and applied as described in Example 1. Example 4.20 parts of extremely finely ground peanut meal (preferably about 200 mesh) preferably white or nearly white in color and from which substantially all the oil has been ex-.

tracted byany well known process; 5 parts borax, 100 parts water, 5 parts pyroxylin varnish, 150 parts water. The peanut meal is mixed with the borax and added to the 100 parts of water. It may be stirred until the protein in the peanut meal is substantially dissolved or the mixture may be heated to about 150 F., to assist in the dissolving. In either case with constant stirring, after about one hours time 5 parts of pyroxylin varnish are added, thoroughly mixed into the peanut meal-borax mixture and the other 150 parts of water added. The procedure may then be followed as described in Example 1.

This-product does not give as smooth a finish coating as when animal glue or alkalized casein is used and the final dry coating requires more sanding and is appartently a somewhat weaker film than when casein is used. I

Example 5.20 parts finely ground soybean meal or flour (preferably about 200 mesh), 5 parts borax, 100 parts water, 5 parts pyroxylin varnish, 150 parts water. The method of procedure is as described in Example 4.

Example 6.20 parts of a seed meal protein substantially free from cellulose and solid substances other than protein; 3 parts borax, 100 parts water, 5 parts pyroxylin varnish, 150 parts water. The method of procedure is the same as in Example 4.

It will be understood that the same pyroxylin varnish which is to be used for coating the article after the application and drying of the filler may be used in makingthe filler. However that used in making the filler can be a cheaper grade, if desired.

In some cases it is also advisable to employ an increased or decreased amount of softener which may be present in the varnish used in making the filler. I do not limit myself to these details however.

It will be understood that the wood, paper, fabric, etc. or articles made therefrom, may be subjected to any desired preliminary treatments, which may not only include mechanical cutting and woodworking treatments, but impregnation, filling, loading, coloring, etc., prior to the treatment forming the process claimed herein.

I call attention to the fact that I do not limit the invention to the degree of fineness. of the meals except as included in the claims.

I claim:

1. A porous absorbent base carrying an undercoating of a dried mixture of an emulsion of pyroxylin varnish with aqueous solution of a highly proteinaceous material, and carrying a top coating thereon, of a dried pyroxylin varnish, said top coating being more firmly united tosaid under coating than would be the case if the pyroxylin varnish were omitted from the under coating composition.

2. ,A wooden base carrying a dried undercoat composed of the solid constituents of pyroxylin varnish intimately blended with dried proteinaceous material, and carrying thereupon and to some extent blended therewith, a dried film of the solid constituents of pyroxylin varnish.

3. A process which comprises applying to a base, an emulsion of a pyroxylin varnish and an aqueous liquid containing a dissolved proteinaceous substance, drying such coating and thereafter applying a pyroxylin varnish and again drymg.

4.'A porous base carrying a priming coating of a soluble protein containing therein and intimately mingled with same, a lesser amount of pyroxylin, and carrying a top coating film of dried pyroxylin lacquer.

5. The method of finishing articles having absorbent surfaces, which consists in producing upon the same a coat of an intimate mixture of a pyroxylin varnish in many times its own volume of an aqueous solution of casein or casein compound, and then superposing thereon a coat of varnish, substantially as described.

6. The method of finishing articles having absorbent surfaces, which consists in producing upon the same a coat of an intimate mixture of a pyroxylin varnish in many times it own volume of an aqueous solution of casein or casein compound, and then superposing thereon a coat of pyroxylin varnish, substantially as described.

'7. The method of finishing articles having absorbent surfaces, which consists in producing upon the same a coat of an intimate mixture of pyroxylin varnish in many times its own volume of a solution of a proteid dissolved in an alkaline aqueous liquid, then superposing thereon a coat of pyroxylin varnish, and then superposing on the latter a coat of varnish containing a nonaqueous solvent, substantially as described.

HENRY V. DUNHAM. 

